delany



(No Model.)

J. H. DELANY.

ELECTRIC HEATER 0R RHEGSTAT.

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:NITED STATES PATENT OFFICE.

JAMES H. DELANY, OF NEV YORK, ASSIGNOR TO EZRA T. GILLILAND, TRUSTEE, OFPELHAM MANOR, NEWv YORK.

ELECTRIC HEATER OR RHEOSTAT.

SPECIFICATION forming part of Letters Patent No. 535,321, dated March5,1895.

Application iiled November' 23, 1894. Serial No. 529.725. (No model.)

.To all whom, in' may concern:

Be it known that I, JAMES H. DELANY, a citizen of the United States,residingin New York city, in the county and State of New York, haveinvented certain new and useful Improvements in Electric Heaters orRheostats, of which the following is a specilication.

Heretofore in this class of devices it has been proposed to mold aroundthe heating or resistance conductors an insulating mass of plasticmaterial that subsequently sets7 or is hardened by baking. Special meansare required to hold the conductors in proper relative position duringthe placement of the mass around them, and difiiculty is experienced insecuring proper relative positions of the conductors or separatesections of the same conductor, in the finished article. A more seriousobjection to this class of such devices is due to the dilerent degreesof expansion and contraction of the conductors and the inclosing mass,and the liability of the mass, when baked, to crack or check, therebeing a tendency to cleavage in the planes in which the conductors lie.Where the mass is not baked but is of a character to set under ordinaryatmospheric conditions, it lacks the requisite hardness and stabilityand is liable to granulation or disintegration because of variations ofatmospheric conditions or changes of temperature due to the heating andcooling of the conductors. In these ways the integrity of position andinsulation of the conductors or sections of conductors, are impaired andthe usefulness of the apparatus deteriorated. It has also been proposedas in the Carpenter enamel rheostat and heater to attach the heating orresistance conductors to a metal base or support by enamel or vitreousmaterial applied as a wash or powder that is hardened by iiring. Theusual process is to rst coat the metal base with a layer of such enamelor vitreous material and harden it by firing. The conductors are thenplaced upon such coating, a layer of powdered or liquid enamel dusted orwashed over them and then fired, several such layers being applied andeach separately tired. Such devices so made have gone into use to someextent, but they are expensive and possess certain objectionablefeatures not incidentie my improved devices.

My invention consists in the employment of abase or support of china,porcelain, terracotta, tiling, or such like earthy or vitreous materialmolded in manufacturing to which the heating or resistance conductorsare united or attached by vitreous enamel, making a homogeneous massunder heat. The material of which the base is composed is in its processof manufacture tired at relatively high temperatures, and may of coursebe molded into such form as is required. The vitreous enamel which is anarticle well known in the art and familiar to those skilled in the artof what is known as enamel rheostats is also fired at a relatively hightempera ture, say from 1,500O to 2,0000, when applied to the base toattach and cover the wires. The enamel and the base of the characterdescribed have practically the same oo-eflicient of expansion. That isto say, the grade of enamel employed may be selected with reference tothe known expansive qualities of the base, so that the coefficient ofexpansion of the enamel and base shall be the same or substantially thesame; and shall be so nearly the same that there is no disruption of theenamel or base when the article is raised to high temperatures either inuse or during the course of its manufacture. The base and enamel havemore or less elasticity that coinpensates for any difference, if suchthere be, between the co-efiicients of expansion of the conductor andenamel and base. Vhen the enamel is applied to the base either in theform of a dust or wash and tired a most perfect junction between the twois secured. One or more coats of enamel may be applied to attach theconductors or semi-conductors to the base and as each coat is relativelythin any difference in expansion between the base, conductor and enamelwill not cause impairment of the enamel coating in firing, and bysuccessive coats and irings a layer of solid enamel of the desiredthickness may be obtained.

Among the advantages incident to my inn vention the following may bementioned:

First. The insulating base or support may IOO be molded in any desiredshape and may be formed with projections around which the heating orresistance conductors may be arranged; or with recesses or apertureswithin which the conductors may be placed, the enamel being then appliedas indicated. W'hether the base or support be so shaped or has a planesurface to which the conductors are secured, no preliminary surfacingwith enamel or insulating material is required, as is necessary where aconducting base is used, that is to say the bare conductors may beplaced directly in position and the enamel coating applied, and asbefore mentioned the enamel and base unite more intimately and securelythan where the base is of metal.

Second. There is no chance for the grounding or short circuiting of theconductors through the base, and inductive action that would occur ifthe base were a mass of metal is eliminated.

Third. Since the base is of non-conducting material there is no chancefor the breaking down of the insulation between the base and conductoras might occur from disruptive discharge or from the use of currents ofhigh intensity or frequency when the base is of metal.

Fourth. The base is a poor conductor of heat and hence will act as areflector of heat and tend to concentrate it at points desiredaccording` to the arrangement of the conductors upon the surface of thebase. This feature is more especially advantageous in the case ofheating and cooking devices.

Fifth. Since the base is of insulating material no special provisionagainst the grounding of terminal contacts of the conductors need beemployed, and after tiring, such terminals may be readily finished in anacid bath a mode of finishing that cannot be readily practiced when abase of iron for instance is used, because the acid will attack thebase, and the use of copper or similar metal as a base would be tooexpensive.

Sixth. Owing to the material of which my devices are constructed, theymay be used in acids or in the presence of gases that would have adestructive effect on a metal base.

Seventh. Since in my apparatus, there is no liability of the insulationbreaking down or the conductors being grounded through the base, thefire risk is greatly reduced.

Having thus described the general charac-A teristics of apparatusconstructed in accordance with my invention I will now refer to a numberof specific forms in which the invention may be embodied, some of whichhave specitic features of novelty in construction and arrangement.

In the accompanying drawings, Figures 1 to 13 inclusive are respectivelydetail views in section illustrating a small portion of apparatusconstructed in accordance with my invention. Fig. 14 is aplan viewindicating a heating or rheostat plate. Fig. 15 is a crossu sectionthereof, and Fig. 16 a plan view of a starting rheostat showing ordinarycircuit connections and indicating the motor. Fig. 17 is a cross-sectionof Fig. 16.

In all the figures the non-conducting base of the character described isindicated by theletter X. The enamel or vitreous coating is indicated byY, and Z indicates the c0nductor.

In Fig. 1 the conductor is laid upon the base and enamel applied tothesurface of the base at the sides of the conductor, but withoutentirelycovering it.

In Fig. 2 the enamel completely covers the conductor.

In Fig. the conductor is disposed in a groove in the base, and enamel isplaced in the groove over the conductor.

Fig. et shows a base formed with an aperture through it within which theconductor is placed with the enamel around it, filling the annular spacebetween the conductor and base.

Fig. 5 shows two base plates or supports with corresponding grooves incontiguous faces. The wire is placed in the aperture or passage way thusformed, and is surrounded by the enamel.

In Fig. G two flat bases or supports are arranged face to face with theconductor between them, and the intervening spaces filled with enamel,the upper and lower faces of the conductor being in contact with theadjacent faces of the plates. A similar arrangement is shown in Fig. 7,except that the layer of enamel between the two plates is of suchthickness as to completely surround the conductors, two of which ofdifferent cross-sectional area are shown.

In Fig. 8 the plate or base is beveled, being thinnest at one edge, thepurpose being to obtain a more equal distribution of heat. Theconductors Z are shown as of different cross-sectional area, and aredesigned to carry currents of different strength or quantity, and themass or thickness of the plate at any particular point is intended to bein proportion to the relative amount of current which the conductor Zthere situated is to carry.

Fig. 9 shows a precisely similar construction, except that the exteriorface of the plate is ribbed or corrugated, the ribs being locatedopposite the respective conductors.

In Fig. 10 the base is corrugated, channels being thereby formed inwhich the conductors are placed, and are covered by a coating of enamelconforming to the shape of the base plate, the intention being to obtaina better radiation and distribution of the heat.

In Fig. 11 the conductor Z isindicated as a flat strip which hasattached to it, or formed thereon a contact terminal P, which extendsabove the enamel and is held in position by it.

Fig. 12 shows a contact terminal P in the ICO ITO

form of a stud, whose shank is seated in a recessin the base, beingretained by the enamel and whose head is exposed above the surface ofthe enamel. The conductor which may be of any shape or cross-section isindicated by the dotted line.

In Fig. 13, the base or support is in the form of a cylindrical rodaround which the heating or resistance conductor is coiled, and retainedin place as in the other cases by the enamel coating.

A coiled conductor is shown in Fig. l4 as arranged upon the face of theplate, with exposed contact terminals P P. Fig. l5 is a cross-section ofthis plate.

Fig. 16 indicates a familiar arrangement of conductors used as avariable resistance or starting box, P being the terminals that may beswept by the switch arm of the device. M indicates the electric motor.

Such constructions as are indicated in Figs. 4, 5, 6 and 7 are intendedmore especially as rheostats, while the other modifications shown areintended more especially as heaters, although they may of course be usedas rheostats.

In all of the illustrations the mass or thickness of the enamel isperhaps greater than is desirable, but this is a point that may bevaried at pleasure.

In such constructions as are shown in Figs. I, 2, 3, 8, 9, l0, Il andl2, the heating or resistance conductors may be located at or slightlybelow the surface of the enamel coating and the base being relatively anon-conductor of heat, the heat will be concentrated l upon or at theenamel surface, a feature that is especially desirable in devices forheating and cooking.

In my improved device as before stated the base is of a vitreous earthycharacter, and is capable of withstanding very high temperatures. Theenamel is of a similar character to relatively high temperatures withoutinjuring it, or in any way affecting its integrity.

I claim as my invention- 1. In an electric heater or rheostat, anonconducting base or support of tiling, porcelain or such likematerial, a heating or resistance conductor arranged thereon,and a layeror coating of vitreous enamel intimately united with the base orsupport-and attaching the conductor thereto.

2. An electric heater or rheostat, consisting of a base or support ofporcelain or such like material, a heating or resistance conductorapplied thereto, and a coating of vitreous enamel intimately united withthe base and conductor, and securely uniting them, and an exposedcontact plate or terminal embedded in and secured in position by theenamel coating.

3. Anelectric heater or rheostat, consisting of a base or support ofporcelain, tiling or similar non-conducting material, a heating orresistance conductor disposed upon the face thereof, and a relativelythin coating of vitreous enamel applied over the conductor and face ofthe base and intimately united thereto.

4. An electric heater or rheostat, consisting of a base or support ofporcelain, tiling or such like non-conducting material, a layer ofvitreous enamel intimately united therewith, and a heating or resistanceconductor embeddedA in and completely surrounded by th layer of enamel.Y

5. An electric heater or rheostat, consisting of a base or support ofvarying thickness, heating or resistance conductors of differentcross-sectional area, and a layer or coating of enamel uniting thebase'and conductors, and intimately united therewith, the conductors ofgreatest cross-section being placed on or opposite that portion of thebase of greatest thickness or mass.

In testimony whereof I have hereunto subscribed my name.

JAMES I-I. DELANY.

lVitnesses:

EDWARD C. DAVIDSON, LLOYD B. WIGHT.

